2013-08-22 Epiphany SW Biosciences 7/\\~ 1 EFTA00506070

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Corporate Overview Mission: To improve the health of patients suffering from serious diseases and unmet medical needs of viral origin and to build shareholder value by developing new antiviral therapies Founded: 2006 Raised: $36m Ownership: Privately Held Headquarters: San Francisco, CA 2 EFTA00506071

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2013-08-22 Epiphany Biosciences’ Investment Thesis Late-stage clinical antiviral company with two attractive, high-potential candidates EPB-348 is a proven drug candidate with multiple “shots-on-goal” = Safe and effective small molecule with broad spectrum antiviral activity = Nocompetition for unmet medical needs * No antiviral approved for shingles associated pain « No approved antivirals for EBV « Paradigm-changing therapeutic approach to a variety of serious diseases, inc/. orphan indications EPB-510 is a Nucleotide Polymerase Inhibitor (NPI) for HCV with a highly competitive preclinical profile versus other high profile leading NPIs Streamlined and efficient development and clinical plans Able to achieve major value-inflection points in multiple clinical programs in approximately 1-2 years Highly experienced team with track record of success Add spreadsheet details 3 EFTA00506072

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Epiphany’s product pipeline Pena seman =s ee Co ee ce co (a2, [evi |[ rater | mamm —][ 4 EFTA00506073

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Valomaciclovir Stearate (EPB-348): Epiphany’s late-stage product opportunity EPB-348 is an effective, late-stage small molecule antiviral * Safe and effective small molecule with broad spectrurn ay activity including Varicella Zoster Virus (VZV), Epstein-Barr Virus (EBV), & Herpes Simplex 1 and 2 (HSV-1/2) History of Valomaciclovir Stearate (EPB-348) * — EPB-348 invented by Medivir AB (MIV-606) * Licensed to Abbott Laboratories - developed through Phase 2a (ABT-606) * Licensed to Reliant Pharmaceuticals - developed tablet formulation (RP-606) . Licensed to Epiphany Biosciences — completed key Shingles & EBV proof-of-concept Phase 2 studies Proven antiviral activity, clinical impact, & safety in multiple Phase 1 & 2 trials * Successful Phase 2b trial for shingles met primary endpoint * Successful Phase 2 trial for EBV and infectious mononucleosis met primary endpoint Highly favorable safety profile * EPB-348 has been dosed to more than 720 patients * More than 130 patients have received mutiple doses of 3 grams or more * No maximum tolerated dase yet determined Well characterized mechanism of action * — Selective viral DNA-polymerase inhibitor * Up to 400-times more potent than Acyclovir with better intracellular concentrations and half-lives 5 EFTA00506074

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2013-08-22 Strong in vitro & preclinical data provide consistent rationale why EPB-348 is more potent than other antivirals Against a variety of different VZV strains in vitro, H2G is up to 400x more potent than acyclovir (ACV) H2G is approx. 250x-better substrate for VZV encoded thymidine kinase than ACV The intracellular concentration of H2G-TP is more than 140x greater than ACV-TP H2G-TP has a longer T,, than ACV-TP EPB-348 has excellent activity in the gold-standard jin vivo Simian Varicella Virus monkey model Lome, DM et of Antiniers, Agents Chamather. 2995, 35.1802; Abele, G et al Anthnal Chem. Chemother. 2981, 2, 283; Soke, KF st al Antireicro. Agents Chereothar. 1901, 17, 1370. 6 EFTA00506075

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Valomaciclovir Stearate (EPB-348) Lead Indication: Shingles & Shingles-Associated Pain 7 EFTA00506076

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2013-08-22 EPB-348 can address the important unmet needs of shingles Differentiating advantages of EPB-348 for shingles * Shingles/Zoster associated pain impact * Wider treatment window * Simpler dosing regimen Proven shingles efficacy * EPB-348 met Phase 2b Shingles Trial endpoints = At lower, less frequent doses, EPB-348 was statistically non-inferior to higher dose Valtrex * Data is directionally consistent with dose dependent improvement De-risked & cost effective late stage clinical development plan * Ability to go against placebo for pain and antiviral endpoints in Phase 3 trials * Phase 3 trials cost significantly offset if performed in countries with [J credits * No competing shingles trials actively recruiting 8 EFTA00506077

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Phase 2b shingles study designed to show EPB-348 efficacy versus Valacyclovir @ Nor-inferiority study (Valacyclovir as comparator) Endpoints @ 20% powered with respect to primary endpoint @ Primary: Time to complete crusting ® Randomized, double-blind, active-controlled, multi-center, parallel-group | @ Secondary: Time to complete cessation of pain © 46 US. dinical centers (© Overall safety parameters Patients were followed for three months with up to 14 visits * Day 28 Final Visit for patients with rash & pain resolution @ Baseline demographics homogeneous & balanced across treatment groups | ** For patients with ongoing rash or pain at Day 28 8373 immunocompetent adult patients randomized into 4 groups ‘3g. arm for PK purposes. Data included in final analysis 9 EFTA00506078

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EPB-348 met Phase 2b primary antiviral endpoint of time-to-complete crusting versus Valacyclovir * EPB-348 once-a-day was statistically hon-inferior Jor GE ° Ree. times-a-day in both the ITT and PP populations for time to complete crusting by day 28 Vi rus Villacyclovir for the treatment of acute Herpes Zaster in imeunccompetent adult: A randemined, double blind, active-contraitled trial” Tenet ‘ned Vvot 2012.84 1728 10 EFTA00506079

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Statistically superior time to complete cessation of pain for patients with pain at Day 28 * Patients who still had pain on Day 28 and were treated with EPB-348 (2 g QD) hada sugtisticaly significant Shorter] time to pain resolution by nearly 2 weeks than the ntrol group (ITT) 11 EFTA00506080

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Incidence of any pain in 250 year old patients was consistently lower for EPB-348 compared to Valacyclovir (OVebes (19 TO) (DEPB.348 (29.00), i & 5 3 : ES § é ¥ Percent of Patients with Pain * There is a natural resolution of pain in a subset of patients with shingles * Antiviral treatment can reduce the incidence of pain and improve time to pain cessation 12 EFTA00506081

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EPB-348 retains its efficacy on day 3 after rash, suggesting a wider treatment window * EPB-348 has statistically significant [fasterto time to complete crusting on Day 3 | for those 50 years and older compared to Walacyelovir\ ITT) a Ton [oa [on [oa [om vfs data |e || 75 [os 112 (1.05) Pow [on [ow [wn fom [om [ele [e[e]o 127 (9.8) wr | ax [oan | oon [om | os | 13 EFTA00506082

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EPB-348 has consistently proven to be a more potent antiviral than Valacyclovir for shingles In vitro * H2Gis up to 400-times more active than ACV against the shingles virus In vivo * EPB-348 is more effective against SVV in a monkey infection model compared to ACV Clinical * Phase 2a clinical shingles trial (Abbott) = Study showed a 30% decrease in pain duration with 750 mg BID, compared to acyclovir * Phase 2b clinical shingles trial (Epiphany) ® 1g EPB-348 QD is statistically non-inferior to 1 g Valtrex TID (3g total} for time-to-complete crusting (PP) = 2g EPB-348 QD had a statistically significant shorter time to pain resolution for patients « Noefficacy dropoff for dosing on Day 3 for EPB-348 (1 & 2 g) unlike Valtrex TID (3g total} 14 EFTA00506083

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2013-08-22 EPB-348 appears to be very safe Results to-date show EPB-348 to be safe and well tolerated * EPB-348 has been dosed to more than 720 patients * More than 130 patients have received multiple doses of 3 grams or more Phase 2b Safety Highlights No study drug discontinuations due to related adverse events Patients with compromised renal function tolerated the drug very well Side-effects were similar between treatment groups and generally mild in nature Two discontinuations from the study based on adverse events deemed not related to study drug Three serious adverse events; all deemed not related to study drug (blind maintained) 15 EFTA00506084

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2013-08-22 Phase 2b/3 pivotal shingles trial to be focused on demonstrating key point of pain differentiation According to the FDA, Valtrex and Famvir have not shown any statistical differences compared to control for pain * Consequently, EPB-348 Phase 2b/3 trials can go against placebo for both antiviral (cutaneous) and pain endpoints Previous clinical studies with Acyclovir, Valtrex and Famvir suggest that they may have some impact on reducing pain & PHN * The pain impact of these antivirals have not been proven in sufficiently powered prospective studies * Use of higher dose levels of these less potent antivirals is not possible as they are already dosed near their maximum approved dosage levels Since EPB-348 is more effective against shingles than Valtrex across a variety of parameters, it is anticipated that EPB-348 could meet both pain and antiviral endpoints in Phase 2b/3 trials, especially against placebo 16 EFTA00506085

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Phase 2b/3 pivotal shingles pain trial design & milestones Treatment Regimen Study Design * Double-blinded, placebo controlled * — Patients aged 50 to 80 years old * Primary endpoint: Incidence of pain at Day 60 Milestones * = 7-month enrollment period * Smonth subject participation period * ~1-Month from Last patient out to database lock * ~— 1-Month from database lock to topline data Highly cost-efficient clinical trial plan * Example: Australia has 45% rebate/ tax credit * Nocompeting shingles trials actively recruiting 17 EFTA00506086

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2013-08-22 Shingles is the first target market for EPB-348, growing to more than $1 Billion Market Potential (in $millions)* * Sales volume in the major pharmaceutical markets projected to grow to >$1 billion (IMS) Key demographic of patients >60 years old is growing with the aging of the global population Annual incidence of shingles in over 60 ! it population is 1.1% | | | Projected 38% growth in the number of | | | : | i shingles patients over 60 years old in {| Ht the Asian markets by 2020, including Ll il >5.4 million cases in China convenience and effective sales and marketing (GSK) Source: IMS extrapolated using governmental demographic projections 18 EFTA00506087

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EPB-348’s advantages for shingles would allow it to dominate the market Existing shingles antivirals No shingles palo henetite: According to the FDA, Valtrex and Famvir have not shown any statistical differences compared to cont: pain Narrow therapeutic index: Approved dosages for shingles are very close to maximum approved dose Limited treatment window: Must be administered within 72 hours of shingles rash onset & efficacy drops off significantly when administered between 48-72 hours * Complicated dosing regimens: Acyclovir: 5-times a day; Valtrex “ & Famvir“: 3 times a day Shingles Vaccine * Minimal market impact of only 1-2% * High co-pay, limited efficacy, unapproved for immunecompromised and those less than 50 years old * — From 2007-2009, Zostavax * uptake was extremely low at 3.9% (Langan, SM et a/ PLoS 2013) Unapproved shingles antivirals * — ASP-2151: Helicase inhibitor development officially suspended in 2011 because of toxicity * — FV-100; No clinical or in vivo demonstration of efficacy = No apparent clinical evidence of FV-100 antiviral activity in Phase 2 trial = No statistical endpoints achieved with respect to pain in Phase 2 trial = Mechanism of action is unknown & no antiviral activity demonstrated in standard in vivo models 19 EFTA00506088

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EPB-348 can be marketed for shingles with a small sales force & with the possibility of early revenues Myth: A large primary-care sales force is required for shingles Asmall sales force can focus on tertiary care centers that see high- volumes of patients such as the urban elderly Anticipate sales of approximately of $200 m using this focused approach Use at tertiary centers will drive further market expansion Revenue after Phase 2b/3 Shingles trial & Ph 2 EBV-transplant may be possible as part of Named Patient Programs 20 EFTA00506089

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Valomaciclovir Stearate (EPB-348) Second Indication: Epstein-Barr Virus (EBV) & Transplant 21 EFTA00506090

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EPB-348 has already demonstrated human clinical proof- of-concept efficacy against Epstein-Barr Virus (EBV) EPB-348 has excellent EBV activity * 10-20-fold more potent in vitro than acyclovir, penciclovir, or foscarnet Phase 2 study of EPB-348 for EBV infectious mononucleosis * Double-blinded, placebo-controlled * Patients received 2 g EPB-348 twice a day for 21 days * Primary endpoint: proportion of subjects with a 100-fold drop in EBV in oral washings Number of subjects with 22 log,, decrease 0.008 in EBV copies/ml at end of treatment Median (mean) decrease in EBV viral load 0.004 during dosing period ° 22 EFTA00506091

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2013-08-22 EPB-348 significantly reduced EBV load ina Phase 2 infectious mononucleosis trial Time to < 1000 copies/mL Oral Sup z $ 6 g & 3 = 20 40 30 | Study pay | j21 Day Treatment Period | Follow Up Period (no drug) ICAAC 2009 23 EFTA00506092

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EPB-348, transplant, & Epstein-Barr Virus (EBV) Background EBV-driven diseases such as Post-Transplant Lymphoproliferative Disorder (PTLD), EBV-encephalitis, and EBV-pneumonitis are important complications following organ transplantation and can result in significant morbidity and mortality No antiviral approved for EBV — no competition, first to market EB8V-driven transplant diseases are eligible as an orphan indication Additionally, Varicella-zoster virus (VZV) frequently causes severe infections in patients who have undergone bone marrow transplantation. EPB-348 and EBV * EPB-348 to be used to treat or prophylaxis for at-risk transplant patients EBV-Transplant Infections and Complications * Over 28,000 solid organ transplants and 10,000 bone marrow transplants in US annually * Early sales possible via Named Patient Program * Potential market of approximately $200 million in the US « Comparable: Valganciclovir (Val) had sales of approx. $300 m in the US = 70% of Val sales were for transplant patients ($200 m} 24 EFTA00506093

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EBV-Transplant Phase 2 Trial (EPB-348) Design & Milestones EPB-348 Treatment 2g BID Regimen Study Design * — Double-blinded, placebo controlled Placebo * 40 transplant recipients with EBV viremia BID * Primary Endpoint: Virologic response to therapy Milestones * 12-month enrollment period * 2 month subject participation period * 1.5-Month from Last patient out to database lock * =1.5-Month from database lock to topline data Success Factors * — Utilizing established clinical network of well-respected, high-volume centers in US and Canada * — Objective endpoint: Virologic response to therapy * — EPB-348 has already proven to be a potent anti-EBV agent in the previous infectious mononucleosis - therefore, high likelinood of success to reduce EBV (as well as VZV) in viremia transplant patients 25 EFTA00506094

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Valomaciclovir Stearate (EPB-348) Additional Indications: Autoimmune & Proliferative Diseases Impacted By EBV 26 EFTA00506095

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EPB-348 for orphan autoimmune & proliferative diseases impacted by herpesviruses (EBV, HSV-1) Background * EBV appears to play an etiological and/or exasperating role in a number of rare, but serious and life-threatening diseases, including: = Multiple Sclerosis, Idiopathic Pulmonary Fibrosis, & Nasopharyngeal Carcinoma EPB-348 and EBV-Autoimmune/Lymphoproliferative disease * = These indications offer potential significant add-on upside for EP8-348 as well as representing a paradigm-changing therapeutic approach to a variety of serious diseases, many of which have orphan status * — Chronic toxicity studies required prior to trials with longer-term EPB-348 dosing Multiple market opportunities in orphan diseases * Multiple Sclerosis (MS) = US prevalence of approx. 400,000 patients; Potential market of approx. $1.5-3 billion based on Copaxone, Avonex, & Rebif comparables * — Idiopathic Pulmonary Fibrosis (IPF) ® US incidence of approx. 20,000-50,000 cases annually; Global market was valued at $2 billion in 2009 * Nasopharyngeal Carcinoma (NPC) ® Accounts for 18% of all cancers in China; Global market of approx. $50-200 million 27 EFTA00506096

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EPB-510 for Hepatitis C (HCV) Preclinical Nucleotide Polymerase Inhibitor (NPI) Program 28 EFTA00506097

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EPB-510 is a highly differentiated approach to HCV Nucleotide Polymerase Inhibitors (NPIs) Recent data from 2012 AASLD confirm the critical role NPIs will play as the cornerstone of future DAA therapies for HCV HCV nucleotide polymerase inhibitors have clustered around a narrow set of structures based primary on 2’-substituted ribose = Very limited IP room to operate = Members of this class have been withdrawn because of toxicity and/or lack of activity However, acyclic nucleosides have a long history of success and safety in the clinic as antiviral agents against herpes virus, HIV, and HBV = Valtrex, acyclovir, & Famvir Epiphany is developing EPB-510 as the first acyclic nucleotide polymerase family to target HCV * Epiphany controls IP around EPB-5S10, a new class of nucleotide-like polymerase inhibitors = Combination of novel scaffold and pro-drug technology = Orally bioavailable pro-drug designed to be liver targeting 29 EFTA00506098

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EPB-510 has an highly competitive in vitro & in vivo profile for an HCV NPI Discovery & Development * Epiphany discovered EPB-510 as part of its internal analogue development program Competitive activity profile * EPB-510 has sub-uM in vitro HCV replicon activity Range of activity very similar to other NPIs including GS-7977 * Series is equipotent against GT 1a & 1b * Unique resistance pattern compared to GS-7977 & INX-08189 © $2827 mutation associated with resistance to 2'-C-methylated compounds (2'Cmec} ® =~ Minimal loss of activity against $282T NSSb mutant HCV replicons : : Excellent PK and safety profile EPB-510 Is orally bioavailable and well-tolerated in vivo Achieves plasma levels well in excess of therapeutic dose (EC.,) Metabolites) derived frorn pro-drug highly unlikely to pose toxicity ue Pisema Conc, of EPES10 ingimL. $8 & & 30 EFTA00506099

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EPB-510 Value Proposition New NPI's are desired for HCV * Next-generation HCV DAA cocktails will likely utilize an NPI * Well-established comparables for preclinical and clinical stage NPIs EPB-510 has a competitive NPI profile Unique and differentiated approach to NPIs EPB-510 has excellent HCV replicon NPI activity Preliminary in vitro pharmacology and toxicity studies complete Scalable synthetic route developed Clear route to clinic * IND-enabling studies can be completed in approximately 6 months * Proof-of-Concept Phase 1b in approximately 9-10 months after IND Strategic objective . Following positive Phase 1b data, seek licensing partner for development through Phases 2 & 3 or sell asset 31 EFTA00506100

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Epiphany Biosciences Corporate Highlights Milestones, Team, & Value Proposition 32 EFTA00506101

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Anticipated Value-Driving Milestones (Crraeounenpiens net ] i] EPB-510 33 EFTA00506102

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Epiphany has a very experienced team Fred Volinsky, MD, Founder, Chairman & CEO = Co-founded CoTherix (acquired by Actelion for $420m); member Ballard Life Science Fund SAB * Previously Managing Director at RCT BioVentures ® Held Directorships at Myometrix, Cylene Pharma, imagine Pharma, Kerberos Proximal Solutions, Catalyst Biosciences «© = Former faculty member at Harvard Department of Emergency Medicine Howard J. Worman, MD, Chief Medical & Scientific Consultant (Prof. of Medicine, Pathology, Cell Biology, Columbia University) Steven Dong, PhD, Director of Chemistry (15+ years of drug discovery & development experience - Kosan Biosciences) Curtis Scribner, MD, MBA, Regulatory Affairs (27+ years regulatory experience; former Medical Officer & Dep. Director at FDA) Paul Flyer, PhD, Clinical Statistics (25+ years of statistical experience - FDA, Amgen, Biogen Idec, ICOS) Solomon Tse, PhD, Chemistry, Manufacturing, & Controls (30+ years CMC experience - 184) Dan Szeto, PhD, QA/QC (30+ years QC/QA/GMP/GLP operations experience - Elan} Chin-chung Lin, PhD, Preciinica! Development (35+ years preclinical development experience - Valeant, (CN, Schering-Plough} Michael Farber, PhD, JD, intellectual Property (27+ years IP experience, Partner at Ditthavong Mori & Steiner) Senior Advisory Board * Robert Gallo, MD, Founder & SAB Chairman (Co-discoverer of HIV; Lasker Award Laureate; Founder & Director of IHV) * Roger Kornberg, PhD, (2006 Nobel Laureate in Chernistry, Teva Board Member, Prof. Stanford University) * Yuan Chang, MD, (Discoverer of two of the seven known human cancer viruses , University of Pittsburgh Cancer Institute} 34 EFTA00506103

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2013-08-22 Epiphany Biosciences’ Value Proposition Late-stage clinical antiviral company with two attractive, high-potential candidates EPB-348 is a proven drug candidate with multiple “shots-on-goal” = Safe and effective small molecule with broad spectrum antiviral activity = Nocompetition for unmet medical needs * No antiviral approved for shingles associated pain « No approved antivirals for EBV « Paradigm-changing therapeutic approach to a variety of serious diseases, inc/. orphan indications EPB-510 is a Nucleotide Polymerase Inhibitor (NPI) for HCV with a highly competitive preclinical profile versus other high profile leading NPIs Streamlined and efficient development and clinical plans Able to achieve major value-inflection points in multiple clinical programs in approximately 1-2 years Highly experienced team with track record of success Add spreadsheet details 35 EFTA00506104

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‘The Information contained in this document & confidential and proprietary to Epiphany Biosciences, inc. CEpiphany"| and ts intended only for the persons to whan it is transmitted by Epiphany, and only to allow these persons to evaluate & possible investment in Epiphary. Epiphany makes no representations of warranties, express or implied, as to the accuracy or completeness of the Information contained herein, Further, ths document ts copyrighted property of Epiphany, Accordingly, any reproduction of this document, in mhole or in part, or the divulgence of any information hergin, without the price written consent of Epiphany, & prohibited. © Epiphany Biosciwnees, Inc. 2006-2033 2013-08-22 36 EFTA00506105